Thermotropic Liquid Crystalline Polycarbonates VI. Synthesis and Properties of Fully Aromatic Liquid Crystalline Polycarbonates by Interfacial or Solution Polycondensation

Several series of fully aromatic liquid crystalline polycarbonates were synthesized by interfacial or solution polycondensation from triphosgene with aromatic diols, such as hydroquinone, 4,4′-biphenyldiol, 2,6-naphthalenediol, Bisphenol A, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenylsulfide, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, methylhydroquinone, t-butylhydroquinone, phenylhydroquinone, and resorcinol, respectively. The structures and thermal properties of the synthesized polycarbonates were examined by FT IR spectroscopy, differential scanning calorimetry (DSC), thermal optical polarized microscopy, and thermogravimetric analysis (TGA). The effects of the structures of polycarbonates on liquid crystalline properties and thermal stability were investigated. The thermotropic LC properties of polycarbonates are strongly dependent on the structures and content of the bent units. The non-linearity of carbonate linkage can be compensated for by bent units in some case.